The present invention relates in general to telecommunication systems, and more particularly, to an apparatus, method and system for providing variable alerting patterns for multiple leg telecommunication sessions.
With the advent of increasingly sophisticated telecommunication services, various proposals have been made to allow a single call, incoming to a telecommunication switch, to branch into multiple, independent outgoing calls (or legs) to different called parties, during the same period of time. These incoming and multiple outgoing calls may be wireline, such as PSTN (public switched telephone network), ISDN (integrated services digital network), or T1/E1 wireline calls, or may be wireless, such as cellular calls or other mobile service communications.
Once such proposal is included in the ANSI-41 specification promulgated by the American National Standards Institute for wireless telecommunication, such as cellular communication, and is referred to as xe2x80x9cflexible alertingxe2x80x9d. The ANSI-41 flexible alerting specification, however, does not include any specific directions or guidelines for implementation and control of such independent, concurrent outgoing multiple leg calls.
Other prior art systems also do not provide for multiple outgoing calls, to different parties, during the same time period. Rather, such known systems provide for individual, sequential calls rather than multiple, concurrent outgoing calls. For example, the incoming call may first alert a home telephone having a first directory number; if the first call is unanswered, that call leg is dropped and a second telephone having a different, second directory number is alerted, such as a cellular phone. If the second call is unanswered, that second call leg is dropped, and a third line having a third directory number is alerted, such as a pager.
As a consequence, a need remains for an apparatus, method and system to implement and control multiple, independent outgoing communication sessions (or call legs) originating from a single incoming call leg. Such an apparatus, method and system should also provide for variable alerting patterns of the multiple, independent outgoing communication legs or links, such as providing concurrent or simultaneous alerting, sequential alerting, cascade alerting, or pyramid alerting. Such an apparatus, method and system should be user friendly and user transparent. Such an apparatus, method and system should also be dynamic and responsive to changing environmental and user conditions which may arise in wireless or wireline communication systems.
A system, apparatus and method are illustrated for providing variable alerting patterns for multiple leg telecommunication sessions, such as for concurrent alerting, sequential alerting, cascade alerting, or pyramid alerting of outgoing call legs for a flexible alerting service. The preferred system embodiment includes a home location register coupled to a mobile switching center. In the preferred system embodiment, a mobile switching center receives an incoming call leg designating a primary directory number (xe2x80x9cDNxe2x80x9d). A subscriber or other user of flexible alerting or other multi-leg communications, typically predefines a group of other directory numbers, referred to herein as secondary DNs, which are to be associated with the primary DN, such that when a call is placed to the primary DN, all of the secondary DNs are alerted. Such a list or grouping may be referred to as a flexible alerting group, or more broadly as an alerting group. The incoming call to the primary DN is then to be processed by a mobile switching center, which then directs the incoming call to the multiple different mobile or wireline secondary DNs of the user""s predefined alerting group, creating multiple different outgoing communication legs to these differing and independent directory numbers. Whichever outgoing call leg is first to answer will receive the call and be connected to the calling party, with the other call legs released (i.e., dropped or torn down, with their corresponding alerting ceased).
To provide for variable alerting patterns for these multiple outgoing call legs, in accordance with the present invention, the home location register has, stored in a memory, a plurality of secondary directory numbers associated with the primary directory number, such as an ANSI compatible pilot directory number. For each secondary directory number of the plurality of secondary directory numbers, the home location register further has stored in the memory three corresponding parameters: first, a corresponding timing delay parameter, referred to as a ring start adjustment time (xe2x80x9cRSATxe2x80x9d) parameter; second, a corresponding no answer time (xe2x80x9cNATxe2x80x9d) parameter; and third, a corresponding termination trigger (no answer termination trigger) parameter. When the mobile switching center receives an incoming call leg designating the primary directory number, it requests this information from the home location register, consisting of the listing of secondary DNs and their corresponding RSAT, NAT, and termination trigger parameters. The mobile switching center then differentially processes and routes each outgoing call leg associated with each secondary directory number, of the plurality of secondary directory numbers, according to its corresponding RSAT, NAT, and termination trigger parameters.
The timing delay (or RSAT) parameter is utilized to independently control the start of alerting of each outgoing call leg, providing any desired variation concerning when each outgoing leg will begin to be alerted. The no answer time (or NAT) parameter is utilized, also on an independent and individual basis, to determine how long each of these outgoing call legs will continue to be alerted prior to being answered, if answered at all. If and when an individual outgoing call leg has remained unanswered (and its no answer time period has elapsed or expired), the termination trigger parameter is utilized to determine how that outgoing call leg is to be treated or handled, such as whether it will be released or torn down, or whether further instructions will be requested.
In accordance with the present invention, varying each of these parameters, independently for each outgoing call leg, provides corresponding variable alerting patterns. In the preferred embodiment, these patterns include concurrent or simultaneous alerting, sequential alerting, cascade alerting, and pyramid alerting.
More specifically, the mobile switching center waits an initial predetermined period of time, determined by a smallest timing delay parameter of a plurality of corresponding timing delay parameters, and following the initial predetermined period of time, the mobile switching center routes a first outgoing call leg to a first secondary directory number, of the plurality of secondary directory numbers, corresponding to the smallest timing delay parameter, Next, the mobile switching center waits a subsequent predetermined period of time, determined by a next smallest timing delay parameter of the plurality of corresponding timing delay parameters, and following the subsequent predetermined period of time, the mobile switching center routes a outgoing call leg to another secondary directory number, of the plurality of secondary directory numbers, corresponding to the next smallest timing delay parameter. Unless a previously routed outgoing call leg has been answered, the mobile switching center continues such corresponding waiting and routing, according to the various timing delay parameters, until all outgoing call legs corresponding to the plurality of secondary directory numbers have been routed.
Concurrently with such differential processing and routing, the mobile switching center monitors each outgoing call leg, and allows each such outgoing call leg to continue to be alerted either until one of the outgoing call legs has been answered, or until the corresponding no answer time has expired for the particular outgoing call leg. For example, depending upon the selected alerting pattern, such as for sequential alerting, following expiration of the NAT for a first outgoing call leg, a second outgoing call leg may begin to be alerted (with a corresponding RSAT), and following expiration of the NAT for the second outgoing call leg, a third outgoing call leg may begin to be alerted (with corresponding RSAT). Also concurrently, following the expiration (if any) of the various NAT parameters, the no answer termination trigger (equivalently referred to herein as a xe2x80x9ctermination triggerxe2x80x9d) parameters are utilized to determine how each such corresponding outgoing call leg is to be treated.
In the various embodiments, for each outgoing call leg, the timing delay parameter and the no answer time parameter are contained as parameters within a Termination List of a modified ANSI compatible LocationRequest RETURN RESULT. To obtain the listing of secondary DNs and their parameters (corresponding to the primary DN) the mobile switching center transmits an ANSI compatible LocationRequest to the home location register. The home location register transmits to the mobile switching center a modified ANSI compatible LocationRequest RETURN RESULT containing, for each secondary directory number of the plurality of secondary directory numbers, the corresponding RSAT, NAT, and Termination Trigger parameters. In addition, the home location register may also transmit an ANSI compatible RoutingRequest to a serving mobile switching center for determining a temporary local directory number for a roaming mobile unit corresponding to a secondary directory number of the plurality of secondary numbers, and will then receive an ANSI compatible RoutingRequest RETURN RESULT from the serving mobile switching center.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings.